The long term objectives of this proposal are to further characterize human 6-phosphofructokinase (PFK; D-fructose-6-phosphate, 1-phosphotransferase EC 2.7.1.11) isozymes in terms of their basic biochemical immunochemical properties; to define ontogenetic alterations and to undertake detailed genetic dissection at the level of gene(s) localization, organization, and mechanism and regulations of expression. These general objectives will be pursued in the following specific studies: (1) Comparative physicochemical, kinetic and structural analyses of three homotetramers and definition of the molecular-genetic basis of various inherited PFK deficiency sttes; (3) Quantitative and qualitative immunochemicl analyses of PFKs from various tissues by using monoclonal antibodies; (4) Definition tissue-specific isozyme distribution patterns; (2) Elucidation of alterations of PFK during early human development, mitogen-induced blastogenesis, and in tissue cultures; (5) Chromosomal assignment of PFKP locus; (6) Isolation in vitro translation of PFK specific mRNAs. These goals will be approached by the following means: (1) Direct isolation and characterization of three homotetramers; (2) Chromatographic resolution of various species; (3) Immunochemical identification of various species using monoclonal antibodies; (4) Protein hybridization technique; (5) Somatic cell hybridization methods. These studies are expected to yield important clues as to the physiological role(s) and significance of PFK isozymes in control of glycolysis as it relates to cell viability, replication, neoplastic transformation, aging and death. At a clinical level, this knowledge may clarify the genetic basis of various inherited PFK deficiency states, at the molecular level.